"We see huge opportunity there (in Southeast Asia). There are 600 million people, the economies are growing, there is a growing middle class," Kevin Strain, president of Sun Life Financial Asia, told Reuters.

Sun Life is now present in seven Asian markets, including four in Southeast Asia.

"This is an important investment for Khazanah. It marks not just an opportunity to invest into an asset in a growth sector, but also brings together a unique commercial partnership among three strong parties in their respective areas," said Khazanah's managing director Azman Mokhtar.

The Canadian company and Khazanah, which owns a 29.9 percent stake in CIMB, will each pay C$293 million.

Sources told Reuters on Sunday that Sun Life and Khazanah had agreed to buy Aviva's Malaysian insurance joint venture.

The deal includes a new 20-year exclusive bancassurance agreement with CIMB Bank. ($1 = 0.9857 Canadian dollars)